Boiler tube manufacturing uses a variety of different sized steel alloy tubes. In order to choose tubes for use in a boiler, it is desirable to know the diameter, wall thickness, composition of the material and/or the hardness of the tubes.
While material properties such as the composition can be identified using a handheld positive material identification device, the measurement of tube dimensions such as the diameter and the wall thickness often necessitate the use of hand-held devices such as vernier calipers, micrometers, and the like. This is a slow and error prone process.
Tubes are generally shipped in bundles and which are stored in a manufacturing location until desired. Random tests are made in an inspection laboratory located at the manufacturing location where the tubes are received. An inspector checks the tubes received against a master manifest, the purchase order and shipping documents, which give a description of the number and types of tubes that were shipped. Measurement of such a large number of tubes with hand-held devices is tedious and limits the number of tubes that are checked. All commonly used boiler regulations (e.g. ASME and EN) specify calculations that must be performed based on the measurements, with accepted criteria for each calculated value.
Typically, an inspection report is created after taking the cross-sectional measurements of a bent tube and performing the desired calculations. The inspection report details whether a particular bend sample failed or passed. This complete process may take several days if performed by hand in an inspection laboratory. It is therefore desirable to use a method that is quicker and that is less error prone.